Convert Sports Betting Odds to Implied Probability

Implied probability is the win rate that a sportsbook's odds are quoting. Read odds correctly and you can compare the book's view to your own — that comparison is the foundation of every +EV bet.

Conversion formulas:

American odds: - Negative odds (favorites): implied = abs(odds) / (abs(odds) + 100) - Positive odds (underdogs): implied = 100 / (odds + 100)

Decimal odds (one formula): - implied = 1 / decimal_odds

Examples: - -110 = 110 / 210 = 52.38% - +120 = 100 / 220 = 45.45% - +250 = 100 / 350 = 28.57% - 1.91 decimal = 1 / 1.91 = 52.36%

The vig adjustment:

A -110 / -110 two-way market implies 52.38% + 52.38% = 104.76%. The 4.76% over 100% is the sportsbook's hold.

To strip vig and find the no-vig (true) probability: - true_p_side1 = implied_p_side1 / (implied_p_side1 + implied_p_side2) - true_p_side2 = implied_p_side2 / (implied_p_side1 + implied_p_side2)

Example. -110 / -110 market: - Implied: 52.38% / 52.38%, sum 104.76%. - True: 52.38 / 104.76 = 50% / 50%.

Pinnacle's de-vig is the gold standard because Pinnacle's hold is the thinnest in the industry. Their two-way markets typically run 102-103% combined, meaning their de-vig produces probabilities very close to actual.

When you bet at a soft book offering, say, +110 on Lakers when the no-vig Pinnacle price for Lakers is -100 (50%), you are getting paid for an outcome the sharpest market believes is 50%. The decimal payout of +110 is 2.10, so EV = (0.50 × 1.10) − 0.50 = +0.05 = 5% expected value. That is a value bet.

CleverBet's quant agent runs this calculation on every game across the major sports daily. Pinnacle de-vig provides the true probability. Every soft book offer is scored. The +EV plays become posted picks.